CVE-2026-103547
Received Received - Intake

ldapd BSD Authentication Result Reuse Vulnerability

Publication date: 2026-09-30

Last updated on: 2026-09-30

Assigner: MITRE

Description
In ldapd in OpenBSD 7.8 before errata 057 and 7.9 before errata 021, delegated BSD authentication results are correlated only by the LDAP child process client file descriptor and LDAP message ID. After a connection closes, a later connection that reuses the same file descriptor and message ID can receive the earlier authentication result. A remote attacker who can reach ldapd can complete a Bind as another identity. A missing connection can also cause a NULL pointer dereference. (ldapd is not enabled by default.)

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Meta Information

Published
2026-09-30
Last Modified
2026-09-30
Generated
2026-10-01
AI Q&A
2026-09-30
EPSS Evaluated
N/A
NVD
CVE-2026-103547
EUVD
EUVD-2026-90259

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
openbsd ldapd *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-863 The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

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Executive Summary

This vulnerability in ldapd for OpenBSD versions 7.8 and 7.9 allows an attacker to impersonate another user by reusing a file descriptor and message ID after a connection closes. The system incorrectly correlates authentication results, enabling unauthorized Bind operations. A NULL pointer dereference can also occur due to missing connections.

Detection Guidance

This vulnerability may be detected by monitoring ldapd logs for unexpected Bind operations or authentication results. Check for reused file descriptors or message IDs across connections. No specific commands are provided in the context.

Impact Analysis

An attacker could gain unauthorized access to systems relying on ldapd for authentication, potentially accessing sensitive data or performing actions as another user. Systems not using ldapd by default are unaffected.

Compliance Impact

This vulnerability could lead to unauthorized access, violating data protection requirements under GDPR and HIPAA. Organizations using affected OpenBSD versions may face compliance risks if ldapd is enabled.

Mitigation Strategies

Apply OpenBSD errata 057 for version 7.8 or errata 021 for version 7.9. Disable ldapd if not in use. Monitor for unauthorized Bind operations and update to a patched version immediately.

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